Honeycomb-like AgNPs@TiO2 array SERS sensor for the quantification of micro/nanoplastics in the environmental water samples

There has been a growing concern over the micro/nanoplastics pollution and treatment. The fast qualitative and quantitative analysis of these small plastic particles is the crucial issues. Herein, a novel honeycomb-like AgNPs@TiO₂ array-based surface-enhanced Raman scattering (SERS) sensor was developed for efficient identification and analysis of the micro/nanoplastics in the environmental water samples. The plasmonic AgNPs were uniformly anchored within the periodic TiO₂ nanocage arrays to form a AgNPs@TiO₂ array. The dual enhancement mechanisms in the AgNPs@TiO₂ hybrid structure endow the SERS sensor high sensitivity to detect trace amount of micro/nanoplastics down to 50 μg/mL with a hand-held Raman spectrometer. Further, this SERS sensor successfully discerns two-component mixtures of the micro/nanoplastics due to the fingerprint feature. In addition, the superior reproducibility (RSD of 9.69%) of the SERS sensor assures the quantitative detection reliability, realizing quantitative analysis of Polystyrene (PS) microplastics in tap water, lake water, soil water and seawater with detection limits of 100 μg/mL, 100 μg/mL, 100 μg/mL, 100 μg/mL and 250 μg/mL, respectively. The recovery rates of PS microspheres in four water environments ranged from 97.6% to 109.7%, with the RSD ranging from 0.49% to 10.23%. This honeycomb AgNPs@TiO₂ array sensor provides a promising application prospect in the detection of micro/nanoplastics contaminants from the environmental water.